Square Footage Calculator

For rectangles and squares, multiply length by width: Area = L × W. For example, a 12 × 15 foot room = 180 square feet. For triangles, use: Area = ½ × base × height. For circles: Area = π × radius². For irregular shapes, divide into rectangles and triangles, calculate each section, then add together. Always use the same units throughout—convert feet and inches to decimal feet first (6 inches = 0.5 feet). For rooms with closets or alcoves, measure the main area plus each extension separately. Deduct permanent fixtures like fireplaces or built-in cabinets from total area.

Divide L-shaped rooms into two rectangles. Measure each separately (length × width), then add both areas. For complex shapes, sketch on paper, divide into simple shapes (rectangles, triangles), calculate each, and sum. Triangles = 0.5 × base × height. This method works for any irregular shape including T-shapes and polygons.

One square yard = 9 square feet (3 ft × 3 ft). To convert sq ft to sq yd, divide by 9. Example: 300 sq ft ÷ 9 = 33.3 sq yd. Carpet is often priced by sq yd. One sq yd = 0.836 m². For quick estimate: sq ft ÷ 10 ≈ sq yd. This calculator shows conversions automatically for convenience.

To convert: sq ft × 0.0929 = m²; m² × 10.764 = sq ft. Quick reference: 100 sq ft ≈ 9.3 m²; 10 m² ≈ 108 sq ft. For dimensions: 1 ft = 0.3048 m; 1 m = 3.281 ft. Most construction materials list coverage in both systems for international use.

Use a tape measure along the longest walls. Measure at floor level, wall to wall. Record in feet and inches (convert inches: divide by 12). For irregular walls, measure at multiple points and use the largest. Laser measurers provide quick accurate readings. Always double-check critical measurements before ordering materials.

For flooring and carpet, include all floor areas you plan to cover—closets, alcoves, and nooks. For painting, closet walls are separate. Real estate typically includes closets in room square footage. For furniture planning, focus on usable floor space excluding closets. Be clear about what you are measuring and why.